A graphic system has heretofore been known which is connected to a processor bus, and in which image data are drawn on a frame buffer based upon instructions from a processor and are displayed on a CRT.
A conventional image data processing system used in a graphic work station where processing must be executed at high speeds, uses a large-capacity processor and a VRAM (dynamic memory with serial port) as a large-capacity memory as disclosed in PIXEL No. 129, pp. 26-34.
Furthermore, a synchronous DRAM has been developed to substitute for an expensive VRAM, and system employing a low-speed graphic apparatus has been described in Electronic Technology, 1993, No. 10, pp. 24-28.
As shown in Japanese Patent Laid-open No. 261969/1986, an image processing system that has heretofore been employed in a facsimile, a printer and a graphic device is employing a high-speed SRAM (static memory) for local processing that makes reference to peripheral pixels and a DRAM (dynamic memory) as a large-capacity memory for storing code data and font data.
In a conventional graphic system in which the graphic processor is connected to a system bus such as a processor, it is not allowed to execute the texture mapping which is necessary for the three-dimensional display at high speeds since the bus speed is low.
In a conventional high-speed image data processing system, furthermore, a special memory is necessary to maintain high performance inviting, however, a serious problem from the standpoint of offering the apparatus at a reduced price. In the conventional image processing system, furthermore, the fact that the two kinds of memories cannot be combined together is a serious bottleneck in the constitution from the standpoint of realizing the device in a small size and in the form of an Large Scale Integration chip "(LSI)".